Every recycler knows that the success of his operation depends entirely on the quality and efficiency of his sorting processes.
Melimax, a construction and demolition (C&D) recycler based in Chateauguay, a suburb of Montreal, was struggling with efficiency issues at his plant in recent years due to the poor performance of the sorting system which required several passes for the same material and a large number of manual sorters.
“We had quite a few issues with our old system, but the main issues were the double and triple handling of the material to bring it up to purity standards, while having a huge amount of pickers. We aimed to reduce our number of pickers as much as possible while having a ‘one in, one out’ system where everything that goes into the system comes out as an end product or trash, ”said Mario Landry, President and Owner. by Melimax. .
In early 2020, Landry began consulting with Sherbrooke OEM on possible solutions to these problems. According to Billy Brasseur, marketing director at Sherbrooke OEM, the company has made the proposal to implement a new sorting technology on the Melimax site in order to increase their recovery rate for both materials over 2 inches and materials. fine, as well as reduce labor costs.
Skeptical at first, the management of the establishment was quickly enthusiastic when presented with the first technical sketch and the financial provisions of the project. According to Brasseur, Sherbrooke OEM mapped the entire project and shared the plans in great detail, not only technically, but also with regard to the financial implications of the project focused on improving recovery rates.
After initial discussions which enabled the company to see the value of modernizing the site’s equipment, Melimax signed a total overhaul of the sorting system.
Manufacturing and design of the system began in May 2020. Installation began in late June and was completed in early October of last year. Melimax began operations with the new system as soon as the installation was completed.
According to Brasseur, “The system was built from the ground up. We didn’t use anything from the old system. The main difference between the new system equipment, however, was the implementation of optical sorters as well as various equipment to sort the fine part of the material.
A thing of vision
Until recently, in the C&D world, only large pieces of wood could be easily salvaged, says Brasseur. This has changed with the advent of more sophisticated sorting methods.
Brasseur says that to help Melimax better recover its wood, Sherbrooke OEM has advocated the introduction of optical sorters, which have been proven on other C&D sites.
Brewer says optical sorters are ideal for this application because they have the capacity to perform hundreds of thousands of ejections every hour. This sorting method has a capture rate of between 95 and 98 percent, depending on the company.
“Now every part larger than 1/8 of an inch is salvageable, which is a huge step forward as it now allows the wood salvage rate to exceed 95% at C&D facilities,” he says.
According to Brasseur, the ability of optical sorters to differentiate between desirable and undesirable materials is one of the main selling points of the system.
“There will always be unwanted material that will be ejected with the desired material. We call this the drag factor, and it is often not taken into account when talking about sorting, when in fact it has a substantial effect on both the catch rate and the purity of your material. . The drag factor is caused by the unwanted material being either too close to the desired material or just somehow attached to the desired material.
Brasseur explains that when programming the ejection parameters of the machines used at Melimax, the company has made sorting out some of these unwanted materials a priority.
“By replacing the quality control done manually by optical sorters, it was possible to increase the quality of the wood, as well as to sort the melamine, the embossed panels and the plastic, which allowed the production of two qualities of wood. distinct with good value, ”he said. Explain.
Regarding the treatment of fines, Sherbrooke decided to design the system as it has done for years in the southern United States, that is, to remove the 1/8 inch fines from the remainder of the 0 – to a 2 inch portion of salvaged material. This was done to recover not only the wood in this fraction, but also the aggregates, which made up an important part of the material.
“The start-up of the Melimax plant quickly made us understand that [separating the 1/8 inch fines from the 0- to 2-inch portion] reduces the total material volume from 0 to 2 inches from 30 percent to less than 15 percent, ”says Brasseur. “In addition, observations to date continue to show that there are as many aggregates in the 0 to 2 inch fraction as in the 2 inch and larger portion, which is not negligible given that [that portion of the 0- to 2-inch material] is usually not recovered at all.
Landry says that thanks to improvements to its sorting system, Melimax is now able to process 50 tonnes per hour, averaging between 400 and 800 tonnes per day. Not only have the improvements at the site resulted in better material recovery, Landry says the new system has helped the company better market its products.
“The first improvement we saw was that we reduced our pickers to five from our initial number of 25, which was a significant expense for us. Not only that, but we get better quality in our products with the Sherbrooke OEM system since it is fully automated. We’ve also seen an increase in our uptime and hourly throughput, ”says Landry. “Perhaps the biggest advantage we have with this system is that the fine materials are sorted. Being able to recover both wood and aggregates from this fraction has had a big impact for us.
This article originally appeared in the March / April issue of Construction & Demolition Recycling magazine. The author is the editor of Construction & Demolition Recycling magazine and can be contacted at email@example.com.